Wireless synchronizing clock system



Jan. 24, 1928.

J. W. BRYCE WIRELESS SYNCHRONIZING CLOCK SYSTEM Filed March 23, 1925 Suva/who:

Patented Jan. 24, 1928.

UNITED STATES PATENT OFFICE.

JAMES W. BRYCE, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR T INTERNATIONAL TIME RECORDING COMPANY OF NEW YORK, OF ENDICOTT, NEW YORK, A CORPORATION OF NEW YORK.

WIRELESS SYNCHRONIZING OLOCK SYSTEM.

This invention relates to a new and improved system for synchronizing a master clock or a plurality of secondary clocks by wireless time impulses received from Arlington or other Government stations. It is more particularly designed to be controlled by any wireless receiving set tuned in to receive the time impulses given out by a Government station and by said impulses 1o controlling the period of activity of a circuit across which is connected the series of clocks which are to be synchronized.

The primary object of the invention is to so control the clocks that they may be maintained in or brought to substantially perfect synchronism with the standard clock controlling the wireless impulses, whether they be initially but of step with the standard clock or brought so by accident or design;

0 to exercise synchronizing control in many difierent forms of system, that is to say, whether the clock be mechanically or electrically driven, or partly so by each of said means; to provide for the use of either alter- 2 nating or direct currents for synchronizing the clocks, and to so organize the synchronizing means that even abnormal departures from true time in the clocks are readily and quickly corrected.

Other and more detailed objects will be hereinafter pointed out in the accompanying specification and claims and shown in the drawings which, by way of illustration, show one and a preferred embodiment of the invention.

Briefly stated, the system comprises a wireless receiving set tuned in to receive the impulses from the standard clock controlled wireless broadcasting set and upon the initial impulses a closed circuit is established through the main bus lines across which the clocks to be synchronized are connected.

This circuit is maintained for a definite period during a portion of which the asynchronous clocks which are too fast are retarded and those which are too slow are accelerated by mechanism self-contained in each clock and which is more fully described in my Patent No. 1,310,780. At the conclusion of this definite period the circuit is broken by a slow acting relay and the clocks thereafter continue to operate under their own source of power until the recurrence of the synchronizing period, when each of those out of step will be again aifected by the circuit established by the wireless set and blIOILght into synchronism with the standard 0 oc The present time signals sent out from Arlington occur daily from 11.55 to 12.00 m., and from 9.55 to 10.00 p.m., and they consist of dots at second intervals omitting the twenty-ninth second of each minute and the last five seconds of each minute, except on the fifty-ninth minute, when the seconds are omitted just before the hour dash. It is the five-minute period marked by the initial dot and the final dash which controls the flow of current in the synchronizing circuits of the clocks, but it is readily understood that any other interval of time used by some other standard time broadcasting system would operate the system equally well.

The initial dot closes a holding circuit for closing the main synchronizing circuit and the final dash operates to throw a slow acting relay to open said circuit.

The wireless receiving set may be kept continually tuned to receive the time signals and throw into cooperation with the system by a clock just prior to the moment of emission of the time signals.

Referring now in detail to the dia am, 1 designates a wireless receiving set 0 standard construction, to the telephone terminals of which is connected a relay 2 which closes circuit 3 through magnet 4 on the first dot of the time signal. Circuits 5 and 6 are leads from the main source of current, which may be alternating or direct, and the energization of magnet 4 causes armature 7 to close circuit 8 and the flow of current from lead 5 through the armature and magnet 4 to lead 6 maintains the magnet energized. This condition causes a current to flow from lead 5, through circuit 9, the lower ortion of armature 7 and thence through t e remainder of the circuit 9 shown in dotted lines and constituting the main synchronizin lines across which the clocks are connecte Circuit 9 is kept closed until circuit Sis opened and this is accomplished when the" slow acting relay 10 is energized by the dash occurring at the end of the time signalling period. This dash produces a current of sufficient duration to close circuit 11 and at the instant contact 12 is made current will flow through circuit 3, contact 12, circuit 13 and thus shunt out magnet 4. Upon deenergization of magnet 4, armature 7 will drop, and synchronizing circuit 9 will be opened as a consequence.

The clock mechanism illustrated is fully described in the above mentioned patent and will not be described herein except in so far as is necessary to understand the present invention. The gears illustrated comprise a time train, and shaft 14 makes one revolution per hour. if the clock is fast it will cause contact 16 to close circuit 17 and thus energize magnet 18 to hold brake 19 against balance wheel 20 and prevent oscillation thereof. Shaft 14 is thereby locked for the amount of time it preceded the standard clock.

Cam 21 is the acceleration cam and when the clock is slow, it closes circuit 22 and energizes magnet 23 to remove latch 24 from the path of the vane on fan 25. This will allow the time train to speed up and rotate shaft 14 until the shoulder of cam 21 is removed from contact with switch 26 and circuit 22 is opened, thereby deenergizing magnet 23. Latch 24: then locks fan 25 and further ac celerated motion of shaft 14 is prevented.

The position illustrated of the cams and shaft 14 is that occurring when the clock is normal. and just at the beginning of the fiveminute interval during which synchronizing circuit 9 is alive. Since the secondary clock is on time or in synchronism with the master clock, the contacts controlled by cam 21 have just opened. Five minutes later, or when synchronizing eriod lapses, contacts 16 will close as a resu t of the passing of the high portion of cam 15. It is evident that during this synchronizing period no current has been allowed to pass through the secondary clock since circuits 17 and 22 have been open during the period of time that circuit 9 was closed.

If a secondary clock should be fast, the drop-off portion of cam 15 would permit contact 16 to close prior to the termination of the period of synchronization with the result that circuit 17 would be energized and magnet 18 would operate to stop the fast secondary clock immediately. The fast secondary clock would remain stopped at its hour position until circuit 9 would become deenergized at the end of the synchronizing period, that is, upon the hour, as indicated by the standard or master clock. Thereafter, the secondary clock would continue to indicate the correct time and to operate un der its own power.

If a secondary clock should be slow, the contacts controlled by cam 21 would remain closed at the beginning of the synchronizing period (in the present arran ement, fiveminutes prior to the hour). Since circuit'9 is energized during this period, a current would flow through circuit 22 and would Cam 15 is a retardation camand,

cause shaft 14 to be advanced very rapidly as has been described hereinbefore. The result is that these contacts would open almost immediately and that thereafter the secondary clock would continue to indicate the correct time and to operate under its own power.

In order to simplify my disclosure, I have chosen the period of synchronism as five minutes because of the daily time signals sent out from Arlington. \Vhile these signals last for a period of five minutes, it is possible to extend the duration of the signals over a longer length of time and in that event the distance between the drop-off portions on cams 15 and 21 would have to be proportionately increased. However a five minute synchronizing period is ample for practical purposes for it permits of a retardation correction up to five minutes and of an acceleration correction which is determinable by the differential gear and step up gearing ratios employed as well as by the length of the high portion on cam 21.

However, if a secondary clock working on a five minute synchronizing period system as described gets ahead of standard time, say seven minutes ahead, that particular clock will be retarded five minutes during the oncoming period of synchronism, and will be brought into synchronism during the next succeeding synchronizing period. It should be evident that the entire system is automatic in its synchronizing capacity and that each secondary clock having connections across circuit 9 will of itself determine whether it shall use electrical energy during a given period of time and whetherand how long it will use that energy to accelerate or retard its operation.

l/Vhat I claim is:

1. The method of synchronizing clocks with and by the action of a wireless receiving set which consists of exciting a synchronizing line by the wireless set and lines receiving therefrom, and at predetermined periods of definite and substantial duration, establishing in and by the clocks, movements of clockmechanism for periods of variable duration dependent on the condition of each clock and in definite time relations to those periods in which a source of current is connected to the synchronizing line by the wireless receiving set, and synchronizing said clocks by varying the clock movements to an extent dependent on the amount of advance or retardation thereof relative to the exact time indicated by the lapse of current. excitation in the synchronizing circuit which lapse is controlled by the wireless receiving set.

2. The method of synchronizing clocks with and by the action of a wireless receiving set which consists of exciting a synchronizing line by the wireless set and lines con-- trolled thereby, at predetermined instances llU - and for definite periods of duration, establishing in and by each clock movements of clock mechanism dependent on the abnormal condition of each clock and having a definite time relation to those periods in which a source of current is. connected to the synchonizing line by the wireless receiving set, and causing a cessation of flow of current in the synchronizing line at a definite instant bythe wireless receiving set.

3. The method of synchronizing, clocks with and by the action of a wireless receiving set which consists of exciting a synchronizing line by the wireless set and lines controlled thereby, at predetermined instances and for definite periods of'duration, establishing in and by each clock, for periods of variable duration dependent on the asynchronized condition of each clock, mechanical and electrical cooperation having a definite time relation to those periods in which a source of current is connected to the synchronizing line by the wireless receiving set and having for its purpose to advance or retard each clock according to its asynchronized condition and during the period of excitation of the synchronizingline.

4. The method of synchronizing clocks with and by the action of a wireless receiving set which consists of exciting a synchronizing line by the wireless set and lines controlled thereby, at predetermined instances and for definite periods of duration, establishing in and by each clock, for periods of variable duration dependent on the asynchronized condition of each clock, movements of clock mechanism having a definite time relation to those periods in which a source of current is connected to the synchronizing line by the wireless receiving set, said movements taking place during the period of excitation of the synchronizing line, the period of excitation of the synchronizing line being automatically terminated at a definite instant by the wireless receiving set.

5. The method of synchronizing clocks with and by the action of a wireless receiving set which consists of exciting a synchronizing line by the wireless set and lines controlled thereby, at predetermined instances and for definite periods of duration, establishing in and by each clock, for periods of variabe duration dependenfi'J-onthe asynchronized condition of each clock, inovements of clock mechanism having a definite time relation to those periods in which a source of current is connected to the synchronizing line by the wireless receiving set, said movements causing the advance or retardation of each clock according to its time relation with thk. initial excitation of the synchronizing line, the period of excitation of the synchronizing line being terminated at a definite instant by the wireless receiving set.

6. In a system of the kind described, the

retarding the operationof the clock during the period of excitation of the synchronizing line and for an amount dependent on the asynchronized condition of the clock.

7. In a system of the kind described, the combination with a wireless receiving set and clock to be synchronized thereby, of a synchronizing circuit closed by an initial impulse transmitted through said receiving set and opened by subsequent impulse transmitted through said receiving set after the lapse of a definite period of time, and circuits, whose excitations are dependent upon the asynchronized condition of the clock and the initial excitation of the synchronizing circuit, for controlling the clock movement.

8. In a system of the kind described, in combination with a wireless receiving set and clock to be synchronized thereby, a relay actuated by impulses from said set, a synchronizing circuit closed by said relay on its first actuation, and another circuit excited by said set after a period of time following the initial actuation of said relay for opening said synchronizing circuit.

9. In a system of the kind described, in combination with a wireless receiving set and clock to he s nchronized thereby, a relay actuated by imp uses from said set for creating a holding circuit, a synchronizing circuit closed by said holding circuit, a plurality of circuits dependent for current from said last named circuit, and means to shunt out said holding circuit controlled by the wireless set for terminating the period of excitation of the synchronizing circuit.

10. In a system of the kind described, in

combination with a wireless receiving set and clock to be synchronized thereby, a relay actuated by impulses from said set, a holding circuit closed on the initial actuation of said relay, a synchronizing circuit closed by the holding circuit, means for opening said holding circuit upon the last impulse transmitted from said receiving set, and a clock having circuits therein connected across the. synchronizing circuit for taking current therefrom when necessary for adjusting the clock.

11. The method of synchronizing one or more clocks by wireless time signals, which consists in connecting by the initial time signal a source of current to a synchronizing circuit for a predetermined interval of substantial duration and connecting with said circuit means in the clock or clocks for retarding or for accelerating their rate for given intervals predetermined by reference the same until the clock or clocks are brought into synchronism with standard time upon which the time signals are based. 10

In testimony whereof I hereunto afiix my signature.

' JAMES W. BRYCE. 

